US5075803A - Signal discriminating device for vtr having expanded dynamic range - Google Patents

Signal discriminating device for vtr having expanded dynamic range Download PDF

Info

Publication number
US5075803A
US5075803A US07/333,901 US33390189A US5075803A US 5075803 A US5075803 A US 5075803A US 33390189 A US33390189 A US 33390189A US 5075803 A US5075803 A US 5075803A
Authority
US
United States
Prior art keywords
circuit
signal
output
discriminating
amplitude
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US07/333,901
Other languages
English (en)
Inventor
Eiji Moro
Hitoshi Akamine
Hiroyuki Torii
Kuniaki Miura
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Assigned to HITACHI, LTD., 6, KANDA SURUGADAI 4-CHOME, CHIYODA-KU, TOKYO, JAPAN, ACORP. OF JAPAN reassignment HITACHI, LTD., 6, KANDA SURUGADAI 4-CHOME, CHIYODA-KU, TOKYO, JAPAN, ACORP. OF JAPAN ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: AKAMINE, HITOSHI, MIURA, KUNIAKI, MORO, EIJI, TORII, HIROYUKI
Application granted granted Critical
Publication of US5075803A publication Critical patent/US5075803A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/02—Analogue recording or reproducing
    • G11B20/06—Angle-modulation recording or reproducing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/76—Television signal recording
    • H04N5/91—Television signal processing therefor
    • H04N5/93—Regeneration of the television signal or of selected parts thereof
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/79—Processing of colour television signals in connection with recording
    • H04N9/7921—Processing of colour television signals in connection with recording for more than one processing mode
    • H04N9/7925—Processing of colour television signals in connection with recording for more than one processing mode for more than one standard
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/79—Processing of colour television signals in connection with recording
    • H04N9/80—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback
    • H04N9/82—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback the individual colour picture signal components being recorded simultaneously only
    • H04N9/83—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback the individual colour picture signal components being recorded simultaneously only the recorded chrominance signal occupying a frequency band under the frequency band of the recorded brightness signal
    • H04N9/832—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback the individual colour picture signal components being recorded simultaneously only the recorded chrominance signal occupying a frequency band under the frequency band of the recorded brightness signal using an increased bandwidth for the luminance or the chrominance signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/79—Processing of colour television signals in connection with recording
    • H04N9/80—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback
    • H04N9/82—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback the individual colour picture signal components being recorded simultaneously only
    • H04N9/83—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback the individual colour picture signal components being recorded simultaneously only the recorded chrominance signal occupying a frequency band under the frequency band of the recorded brightness signal
    • H04N9/832—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback the individual colour picture signal components being recorded simultaneously only the recorded chrominance signal occupying a frequency band under the frequency band of the recorded brightness signal using an increased bandwidth for the luminance or the chrominance signal
    • H04N9/833—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback the individual colour picture signal components being recorded simultaneously only the recorded chrominance signal occupying a frequency band under the frequency band of the recorded brightness signal using an increased bandwidth for the luminance or the chrominance signal with selection of the conventional or the increased bandwidth signal, e.g. VHS or SVHS signal selection

Definitions

  • the present invention relates to a signal discriminating device having a function to classify input signals supplied thereto based on a spectrum of the signal as information for discrimination, and in particular, to a signal discriminating device suitable for an automatic discrimination of a playback mode of a video tape recorder (VTR) such as one represented by an S-VHS-VTR having two systems of FM standards.
  • VTR video tape recorder
  • a signal discriminating circuit device of this kind has been described, for example, as a constitution in pages 24 to 27 of a Japanese article "Television Technology", August '87, and such a known technology has been disclosed in the U.S. Pat. No. 4,786,986 assigned to the present assignee (block 12, FIGS. 7-10).
  • FIG. 7 shows an example the conventional device described in the Japanese article above.
  • the signal discriminating device develops, as represented by the S-VHS-VTR, a signal discriminating function in a VTR having two kinds of FM standards in an FM luminance signal processing such that a difference between reproduced FM signal spectra is detected so as to output a high level or a low level depending on a mode determined by the detection.
  • Description will next be given of a case where the circuit device is applied to the S-VHS-VTR.
  • an input signal is a playback or reproduced FM signal.
  • the high-frequency output is generally lowered.
  • a peaking circuit 2 to correct the decrease in the high-frequency output, and in general, the peaking circuit 2 is adjusted to develop a peaking characteristic associated with the peaking frequency ⁇ p ⁇ 7 to 8 MHz.
  • a reproduced FM signal corrected by the peaking circuit 2 passes through an amplifier 10 and is then supplied to an S-VHS-band-pass filter (BPF) 11 and a VHS-band-pass filter (BPF) 12.
  • BPF S-VHS-band-pass filter
  • BPF VHS-band-pass filter
  • DC direct-current
  • the output DC potential of the smoothing circuit 14 becomes greater than that of the smoothing circuit 13.
  • a comparator 15 effects a compare operation among three input DC potential values.
  • the output DC potential of the smoothing circuit 13 takes the highest value
  • the output from a hold controller 17 indicates the S-VHS mode (let us assume here the output is at a high level in this case).
  • the output from a hold controller 17 is set to a lower level and hence indicates the VHS mode.
  • FIG. 8 shows a hold control characteristic of the output mode of the hold controller 17 when the amplitude and frequency of the input signal to the amplifier 10 are changed.
  • the value of the output mode in a range of the amplitude of the input signal not exceeding 100 mVpp, the value of the output mode is kept unchanged. That is, the range is a dead zone for the input signal.
  • the width of the amplitude dead zone can be arbitrarily set by changing the value of the reference potential 16.
  • the previous value of the discrimination output is generally held in a form of an electric charge by use of a capacitor.
  • the leakage of the charge cannot be avoided, and in order to prevent the effect thereof, it is necessary to increase the size and capacity of the capacitor.
  • the value of the time constant increases and hence the response speed of the circuit is lowered, which leads to a problem in the practical operation.
  • the discriminating device according to the U.S. Patent above also employs a capacitor to hold the signal and hence is attended with the similar problem.
  • Another object of the present invention is to provide an automatic playback mode discriminating device formed in an integrated circuit (IC) which has a large dynamic range so as to prevent a wrong discrimination due to an amplitude deviation of a reproduced FM signal of a VTR.
  • IC integrated circuit
  • a signal discriminating device including a discriminating circuit, an automatic gain control (AGC) circuit for setting an amplitude of an input signal to a constant value and for expanding a dynamic range of the signal discriminating circuit, said signal discriminating circuit being coupled to the output of said AGC circuit, a latch circuit connected to an output from said signal discriminating circuit so as to develop a function to keep a previous value of a discrimination output, and an amplitude detecting circuit for detecting a magnitude of an amplitude of the input signal prior to said AGC circuit such that the reliability of the discriminating operation is improved by controlling the latch circuit based on an output from the amplitude detecting circuit as noise information.
  • AGC automatic gain control
  • the gain of the amplifier is automatically changed to set the output amplitude to a fixed value.
  • the amplification gain is increased; whereas, for a large amplitude of the input signal, the amplification gain is decreased, so that the output amplitude is held at a fixed value for a broad range of the amplitude of the input signal namely, the dynamic range is expanded.
  • a range of the input signal in which the amplitude of the AGC output signal is kept at a fixed value will be referred to as an AGC dynamic range herebelow.
  • the amplitude of the input signal received by the signal descriminating device is not subjected to the influence caused by the dispersion of the reproduced FM signal, and hence there is attained an FM signal having substantially a constant amplitude.
  • the input signal to the AGC circuit does not include any signal component, namely, only a noise is inputted
  • a noise is amplified by the AGC circuit so as to be fed to the signal discriminating circuit, which may easily lead to an incorrect discrimination.
  • the amplitude of the signal not having passed through the AGC circuit is detected to effect a comparison between the detected amplitude and a threshold value separately set.
  • the threshold value is established such that a large input amplitude is assumed for an ordinary signal input and that a small input amplitude is assumed for a noise input and for an input of quite a small signal associated with a large deterioration of the signal-to-noise ratio.
  • the input signal dynamic range in which a stable discriminating is possible can be set to a very large value, and the output hold operation to hold the output in a case of an input of quite a small signal is provided to prevent the erroneous discrimination in a special playback operation or the like, in consequence, there can be implemented a signal discriminating device developing a high performance.
  • FIG. 1A is a block diagram showing the structure of a reproducing system of the VTR to which the present invention is applied as an embodiment
  • FIG. 1B is a block diagram schematically showing a discriminating device of an embodiment according to the present invention.
  • FIG. 2 is a block diagram showing in detail an example of a signal discriminating circuit 1 of FIG. 1B;
  • FIG. 3 is a graph showing characteristics of an S-VHS-BPF 11 and a VHS-BPF 12 of FIG. 2;
  • FIG. 4 is a graph showing a characteristic of an AGC circuit of FIG. 1B;
  • FIG. 5 is a graph showing an example of a characteristic of a signal discrimination of the system of FIG. 1B according to the present invention.
  • FIGS. 6A and 6B respectively are a head locus diagram and a reproduced output envelope diagram showing an operation in the case where the present invention is applied to a special playback (reproducing) operation of a VTR;
  • FIG. 7 is a schematic block diagram showing an example of the conventional discriminating device.
  • FIG. 8 is a graph showing characteristics associated with the VHS and S-VHS modes.
  • 21 denotes a magnetic tape, 22 a magnetic head, 23 a preamplifier, 24 a low-pass filter (LPF) for extracting a C component only from a reproduced signal picked up from the head 22, 25 a reproduced C signal processing circuit for restoring the frequency of the subcarrier to the original frequency of 3.58 MHz, 26 a band-pass filter (BPF), 27 an adder, 28 a switch, 29 a first peaking circuit for the conventional recording method, having a frequency characteristic curve with a peak frequency of 4.4 MHz, 30 a second peaking circuit for the high-band recording method, having a frequency characteristic with a peak frequency of 7.0 MHz, 31 a reproduced Y signal processing circuit including such as an FM demodulator circuit, a de-emphasis circuit, whose characteristics are changed over in accordance with the output of a discriminating device 32, 33 an output terminal at which an original video signal appears in a form of the Y signal and the C signal multiplex
  • LPF low-pass filter
  • An FM AGC circuit 35 is provided at the preceding stage of the first and second peaking circuits 29 and 30 and the output of the preamplifier 23 is applied to each of the LPF 24, the discriminating device 32 and the FM AGC circuit 35.
  • the recording method of the reproduced video signal is identified on the basis of the output of the discriminating device 32 and a signal indicative of the result of identification is applied to the switch 28 to allow switching of the outputs of the first and second peaking circuits 29 and 30 in accordance with the type of recording method thus identified.
  • FIG. 1B is a block diagram of a signal discriminating device showing an embodiment according to the present invention.
  • This configuration includes a signal discriminating circuit 1, a peaking circuit 2, an automatic gain control amplifier 3 (to be referred to as an AGC amplifier herebelow) as a constituent element of an AGC circuit, a level detecting circuit 4 (to be referred to as an AGC detecting circuit herebelow) as a constituent element of an AGC circuit, an amplifier 5, a smoothing circuit 6, a reference voltage generating circuit 7, a comparator 8, and a latch circuit 9.
  • FIG. 2 shows in detail an example of the constituent elements of the signal discriminating circuit 1 of FIG. 1 in which reference numerals 10 to 15 indicate elements functioning to provide similar operations as those of the conventional example of FIG. 7.
  • the reference voltage generating circuit 7 is however unnecessary.
  • the signal discriminating section 1 when the amplifier 10 is supplied with a reproduced FM output signal obtained by reproducing a signal recorded in either one of the FM standards, namely, the VHS or S-VHS mode, there is developed a function in which it is judged to determine whether the FM standard of the input signal is the VHS mode or the S-VHS mode so as to produce change-over control signals to effect a switching operation on the reproducing (playback circuit) system and to turn a mode indication light emitting diode on.
  • FIG. 8 shows an example of a characteristic of the signal discriminating circuit 1 wherein the input signal level for which the discrimination can be achieved is in a range from 100 mVpp to 600 mVpp.
  • the system of FIG. 1 is provided with an AGC circuit including the AGC amplifier 3 and the AGC detecting circuit 4.
  • FIG. 4 shows an example of an input/output characteristic of the AGC circuit 3 and 4.
  • the output amplitude is substantially constant, namely, 400 mVpp.
  • the discrimination characteristic of the signal discriminating circuit 1 is as shown in FIG. 8, and hence the amplitude of 400 mVpp is quite suitable for the discrimination. In consequence, as a result of provision of the AGC circuit 3 and 4 above, the signal discrimination is possible when the amplitude of the signal inputted to the AGC circuit 3 is in a range from 10 mVpp to 1 Vpp.
  • the gain of the reproducing preamplifier when the gain of the reproducing preamplifier is set to about 66 dB, the signal-to-noise ratio (to be abbreviated as S/N ratio herebelow) is greatly deteriorated for a signal of which the output amplitude is about 50 mVpp or less, and hence this signal is not suitable as input information for the discriminating circuit, namely, there exists a danger that an incorrect discrimination easily takes place.
  • the reproducing preamplifier delivers an output attended with a noise associated with an amplitude of 50 mVpp.
  • the configuration of FIG. 1 includes the amplifier 5, the smoothing circuit 6, the reference voltage generating section 7, the comparator 8, and the latch circuit 9. Description will next be given of operations of these elements.
  • the amplifier 5 is supplied as an input thereto a signal which has not passed the AGC circuit 3.
  • the amplifier 5 delivers an output which is converted into a DC signal through the smoothing circuit 6 so as to be supplied to the comparator 8.
  • the comparator 8 then compares an output from the smoothing circuit 6 with an output from the reference voltage generating circuit 7 which supplies a comparison reference, thereby outputting a signal at a high level or a low level depending on the result of the comparison.
  • the amplifier 5 is disposed to facilitate the compare operation and hence is not necessarily included in this configuration.
  • the gain and the reference voltage 7 are set for the amplifier 5 such that the output from the comparator 8 is respectively set to the high level and the low level when the amplitude of the input signal supplied to the amplifier 5 is at least 100 mVpp and less than 100 mVpp, respectively.
  • the comparator 8 delivers an output to be fed to the latch circuit 9 including a flip-flop circuit.
  • Table 1 shows a truth value table of the latch 9.
  • digits 1 and 0 assigned for the G input indicate the high level and the low level, respectively. That is, when the amplitude of the input signal supplied to the amplifier 5 is at least 100 mVpp, the output Q from the latch circuit 9 delivers the discrimination output directly from the signal discrimination circuit 1. In this situation, for the input signal supplied to the signal discriminating circuit 1, the S/N ratio is favorable and the amplitude is kept at 400 mVpp, which facilitates the stable discriminating operation. In addition, when the amplitude of the input signal fed to the amplifier 5 is smaller than 100 mVpp, for the output Q from the latch circuit 9, the previous output value is kept unchanged (latched state).
  • FIG. 5 shows an example of the discrimination characteristic of the circuit configuration of FIG. 1 described above.
  • the upper limit of the dynamic range is expanded to exceed the input amplitude of 1 Vpp and there is provided the latch operation above; in consequence, in the range of the input amplitude not exceeding 100 mVpp related to noise, the hold mode is set to hold the previous value of the discrimination output.
  • FIGS. 6A and 6B are diagrams showing a special operation of the VTR such as a search operation or a still operation to which the present invention is effectively applied wherein FIG. 6A shows the head locus and FIG. 6B shows the reproduced output envelope.
  • a trace operation is generally achieved in a range including two or more tracks.
  • the azimuth of the head A is different from that of the head B, and hence the reproduced output envelope develops a change in which the amplitude is increased and decreased in an alternate fashion as shown in FIG. 6B.
  • the recording track has an azimuth equal to the azimuth of the playback head
  • a large value is obtained for the reproduced or playback output envelope and a favorable S/N ratio is developed.
  • a small value is obtained for the playback output envelope and a deteriorated S/N ratio is developed.
  • the signal discrimination is carried out only in a period T 2 in which the S/N ratio is favorable, whereas there is effected an operation to hold the output in a period T 1 in which the S/N ratio is deteriorated. In consequence, the erroneous operation is prevented also in the special playback operation.
  • the band-pass filters 11 and 12 are configured with active filters, and a capacitor and a resistor included in a time constant circuit which is conventionally provided as an external device and which is disposed for the purpose of adjusting the characteristic of said filters 11 and 12 are constituted with variable capacitance elements, so that the time constant is adjusted by externally applying a voltage thereto.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Multimedia (AREA)
  • Television Signal Processing For Recording (AREA)
US07/333,901 1988-04-06 1989-04-06 Signal discriminating device for vtr having expanded dynamic range Expired - Lifetime US5075803A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP63-82915 1988-04-06
JP63082915A JP2690933B2 (ja) 1988-04-06 1988-04-06 信号判別装置

Publications (1)

Publication Number Publication Date
US5075803A true US5075803A (en) 1991-12-24

Family

ID=13787547

Family Applications (1)

Application Number Title Priority Date Filing Date
US07/333,901 Expired - Lifetime US5075803A (en) 1988-04-06 1989-04-06 Signal discriminating device for vtr having expanded dynamic range

Country Status (4)

Country Link
US (1) US5075803A (ja)
JP (1) JP2690933B2 (ja)
KR (1) KR920008108B1 (ja)
DE (1) DE3911162C2 (ja)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU648770B2 (en) * 1990-01-31 1994-05-05 Sony Corporation Recording mode discrimination circuit
US5418661A (en) * 1991-04-27 1995-05-23 Rohm Co., Ltd. Active filter characteristic changeover circuit for use in a VCR
US5438558A (en) * 1990-03-07 1995-08-01 Canon Kabushiki Kaisha Image signal apparatus including clamping processing of image signal
EP0735539A1 (en) * 1995-03-31 1996-10-02 Lg Electronics Inc. Double deck video cassette tape recorder
US5978546A (en) * 1995-01-17 1999-11-02 Hitachi, Ltd. Digital/analog compatible video tape recorder
US6931197B1 (en) 1999-10-25 2005-08-16 Samsung Electronics Co., Ltd. Frequency modulation (FM) recording apparatus of video tape recorder

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01300474A (ja) * 1988-05-30 1989-12-04 Hitachi Ltd 磁気記録再生装置
EP0440167B1 (en) * 1990-01-31 1996-03-20 Sony Corporation Recording mode discrimination circuit
JPH05151705A (ja) * 1991-11-27 1993-06-18 Hitachi Ltd ビデオ信号処理装置および信号処理回路
JPH09214872A (ja) * 1996-01-30 1997-08-15 Sony Corp 情報信号処理装置及び情報信号処理方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0154221A2 (en) * 1984-02-13 1985-09-11 Sony Corporation Video signal reproducing circuit for a video tape recorder
EP0265930A2 (en) * 1986-10-31 1988-05-04 Hitachi, Ltd. Magnetic recording and reproducing apparatus
EP0287682A1 (en) * 1986-10-28 1988-10-26 Mitsubishi Denki Kabushiki Kaisha Apparatus for magnetically recording and reproducing video signals
EP0335655A2 (en) * 1988-03-29 1989-10-04 Sony Corporation Method and apparatus for detecting the mode of a frequency-modulated signal

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0760567B2 (ja) * 1987-06-15 1995-06-28 松下電器産業株式会社 記録モ−ド判別装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0154221A2 (en) * 1984-02-13 1985-09-11 Sony Corporation Video signal reproducing circuit for a video tape recorder
EP0287682A1 (en) * 1986-10-28 1988-10-26 Mitsubishi Denki Kabushiki Kaisha Apparatus for magnetically recording and reproducing video signals
EP0265930A2 (en) * 1986-10-31 1988-05-04 Hitachi, Ltd. Magnetic recording and reproducing apparatus
US4786986A (en) * 1986-10-31 1988-11-22 Hitachi, Ltd. Magnetic recording and reproducing apparatus
EP0335655A2 (en) * 1988-03-29 1989-10-04 Sony Corporation Method and apparatus for detecting the mode of a frequency-modulated signal

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU648770B2 (en) * 1990-01-31 1994-05-05 Sony Corporation Recording mode discrimination circuit
US5438558A (en) * 1990-03-07 1995-08-01 Canon Kabushiki Kaisha Image signal apparatus including clamping processing of image signal
US5418661A (en) * 1991-04-27 1995-05-23 Rohm Co., Ltd. Active filter characteristic changeover circuit for use in a VCR
US5978546A (en) * 1995-01-17 1999-11-02 Hitachi, Ltd. Digital/analog compatible video tape recorder
US6272285B1 (en) 1995-01-17 2001-08-07 Hitachi, Ltd. Digital/analog compatible video tape recorder
US6798979B2 (en) 1995-01-17 2004-09-28 Hitachi, Ltd. Digital/analog compatible video tape recorder
US20050036760A1 (en) * 1995-01-17 2005-02-17 Hiroya Abe Digital/analog compatible video tape recorder
US7263272B2 (en) 1995-01-17 2007-08-28 Hitachi, Ltd. Digital/analog compatible video tape recorder
EP0735539A1 (en) * 1995-03-31 1996-10-02 Lg Electronics Inc. Double deck video cassette tape recorder
US5715351A (en) * 1995-03-31 1998-02-03 Lg Electronics, Inc. Double deck video cassette tape recorder with video signal processing circuit
US6931197B1 (en) 1999-10-25 2005-08-16 Samsung Electronics Co., Ltd. Frequency modulation (FM) recording apparatus of video tape recorder

Also Published As

Publication number Publication date
JP2690933B2 (ja) 1997-12-17
DE3911162A1 (de) 1989-10-19
KR920008108B1 (ko) 1992-09-22
JPH01256004A (ja) 1989-10-12
KR890016549A (ko) 1989-11-29
DE3911162C2 (de) 1993-10-28

Similar Documents

Publication Publication Date Title
US5075803A (en) Signal discriminating device for vtr having expanded dynamic range
US4398219A (en) Switching apparatus for the recording and reproducing of PCM or video signals
KR920004127B1 (ko) 자기기록 재생장치
US5220427A (en) Magnetic reproducing apparatus having circuit for preventing reversal of white peak
US5148329A (en) Magnetic recording/reproducing circuit system including a temperature controlled amplitude control circuit for a video signal
EP0579198B1 (en) Magnetic recording control device
US5589946A (en) Video signal reproduction apparatus replacing drop-cut signal portions
US3356794A (en) Device for reducing noise in f. m. carrier recording
US5765053A (en) Recording/reproducing apparatus detecting a misrecorded portion
US4897608A (en) Circuit arrangement for frequency-modulated picture signals
US4549225A (en) Color video signal processing circuit for performing level control and time axis deviation compensation
US5260843A (en) Magnetic recording and reproducing apparatus with individual correction of amplitude variations of recording currents supplied to plural rotary magnetic heads
US5323274A (en) Reproducing apparatus
US5982975A (en) Video signal copying apparatus
US5510853A (en) Automatic gain control circuit for stabilizing the level of a reproduced color signal
US5523855A (en) Discriminating device for automatically discriminating between recorded video signal reproduction modes
US5097336A (en) Signal processing apparatus
US6118919A (en) Video signal processor
JP2987890B2 (ja) カラー映像信号の再生装置
US6185361B1 (en) Information signal processing apparatus for detecting both dropout of information signals and absence thereof
JP3334187B2 (ja) Ｖｔｒの記録速度モード判別回路
US6519409B1 (en) Apparatus for recording a high quality signal
KR100270253B1 (ko) 비디오 테이프 재생 장치
KR890005007B1 (ko) 자기 기록 재생 장치
JP2942067B2 (ja) 磁気記録再生装置

Legal Events

Date Code Title Description
AS Assignment

Owner name: HITACHI, LTD., 6, KANDA SURUGADAI 4-CHOME, CHIYODA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:MORO, EIJI;AKAMINE, HITOSHI;TORII, HIROYUKI;AND OTHERS;REEL/FRAME:005061/0440

Effective date: 19890327

STCF Information on status: patent grant

Free format text: PATENTED CASE

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12